Multimodality imaging of neoplastic and nonneoplastic solid lesions of the pancreas

Adult Pancreatoblastoma With Liver Metastasis Diagnosed by 18F-FDG PET/CT and 2 Years' Postoperative Follow-up

Pancreatoblastoma is an extremely rare malignant tumor of the pancreas. Most patients are infants and children; however, a few cases have been reported in adults. Herein, we present the case of a 49-year-old man with pancreatoblastoma and liver metastasis who underwent preoperative multimodal imaging, in which F-FDG PET/CT showed a markedly increased F-FDG uptake in the metastatic lesion and a slightly increased uptake in the primary lesion. Subsequently, the patient underwent complete resection of the primary and metastatic lesions. No recurrences or metastases were found in 2 years of follow-up.

Pitfalls in the MDCT of pancreatic cancer: strategies for minimizing errors

Multidetector computed tomography (MDCT) is a widely used cross-sectional imaging modality for initial evaluation of patients with suspected pancreatic ductal adenocarcinoma (PDAC). However, diagnosis of PDAC can be challenging due to numerous pitfalls associated with image acquisition and interpretation, including technical factors, imaging features, and cognitive errors. Accurate diagnosis requires familiarity with these pitfalls, as these can be minimized using systematic strategies. Suboptimal acquisition protocols and other technical errors such as motion artifacts and incomplete anatomical coverage increase the risk of misdiagnosis. Interpretation of images can be challenging due to intrinsic tumor features (including small and isoenhancing masses, exophytic masses, subtle pancreatic duct irregularities, and diffuse tumor infiltration), presence of coexisting pathology (including chronic pancreatitis and intraductal papillary mucinous neoplasm), mimickers of PDAC (including focal fatty infiltration and focal pancreatitis), distracting findings, and satisfaction of search. Awareness of pitfalls associated with the diagnosis of PDAC along with the strategies to avoid them will help radiologists to minimize technical and interpretation errors. Cognizance and mitigation of these errors can lead to earlier PDAC diagnosis and ultimately improve patient prognosis.

Clinical manifestations and multi-slice computed tomography characteristics of solid pseudopapillary neoplasms of the pancreas between males and females

Background

Solid-pseudo papillary neoplasms of pancreas (SPNP) are rare in men and are often misdiagnosed. This study aimed to analyze the clinical and multi-slice computer tomography (MSCT) features of patients with SPNP, and examine the differences between males and females.

Methods

In this retrospective cohort study, the clinical and imaging data of 29 patients with histolopathologically confirmed SPNP (seven males and 22 females) that underwent radical resection, and underwent preoperative MSCT at the First People’s Hospital of Lianyungang between August 2010 and December 2018 were collected. All MSCT images were reviewed by two radiologists; disagreements were ruled by a third one.

Results

The median age of the 29 patients with SPNP was 30 (range, 12–70) years. The male patients were older than the female patients [median, 56 (28–66) vs. 29 (12–70), P = 0.012]. The median tumor size was 3.9 (range, 2.0–6.4) cm in the male SPNP patients, which was significantly lower than the 7.0 (range, 4.6–14.6) cm in the female patients (P < 0.001). The calcification rate of the SPNP was significantly higher in male than in female patients (P = 0.013). The percentage of solid tumor was higher in males than in females (P = 0.036). Capsule, bleeding, and enhancement in the arterial and venous phases were not significantly different between the male and female patients (all P > 0.05).

Conclusion

The imaging features of male SPNP are distinct from those of female patients. In males with pancreatic lesions, MSCT generally shows relatively small lesions with higher percentages of solid components and calcification, with typical enhancement suggesting SPNP.

Pancreatic Head Mass: A Rare Manifestation of Granulomatosis With Polyangiitis

Granulomatosis with polyangiitis may rarely present as an inflammatory pancreatic mass and mimic pancreatic cancer. We report a 73-year-old man who presented with fever and weight loss. Computed tomography imaging demonstrated a mass in the pancreatic head along with multiple cavitary pulmonary nodules. Our differential included metastatic pancreatic cancer vs an autoimmune process. Positive cytoplasmic antineutrophil cytoplasmic antibodies coupled with the lung biopsy findings established the diagnosis of granulomatosis with polyangiitis, a very rare cause of pancreatic masses. After completion of immunosuppressive therapy, magnetic resonance imaging demonstrated no evidence of a pancreatic mass. More studies are required to establish the management of these masses.

Perivascular Epithelial Cell Tumor of the Pancreas Diagnosed Preoperatively by Endoscopic Ultrasound-guided Fine-needle Aspiration

We herein report a 49-year-old woman with a perivascular epithelial cell tumor (PEComa) of the pancreas. Imaging studies demonstrated a relatively well-demarcated mass, measuring approximately 40 mm in diameter, located in the pancreatic tail. It was heterogeneously enhanced almost to the same degree as the surrounding pancreatic tissue in both the arterial and portal venous phases. We performed endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) using the Acquire^® 22-gauge needle and preoperatively obtained a definitive diagnosis with a sufficient sample. Clinicians should consider pancreatic PEComa in their differential diagnosis of patients with a pancreatic mass.

Endoscopic ultrasonography for pancreatic solid lesions

The incidence and mortality rates of pancreatic cancer, which has a poor prognosis, are rising rapidly. Endoscopic ultrasonography (EUS) provides superior spatial resolution compared with other imaging modalities such as transabdominal ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), and it is considered among the most reliable and efficient diagnostic modalities for pancreatic diseases. In this review, we show that EUS is useful for detection of pancreatic solid lesions and staging of pancreatic cancer. EUS also plays an important role in screening patients with high-risk factors for pancreatic cancer. Although EUS is useful for detection of small pancreatic lesions, pancreatic lesions are difficult to characterize using this modality, because most pancreatic solid lesions appear hypoechoic on EUS. From this point of view, contrast-enhanced harmonic EUS (CH-EUS) plays an important role in the differential diagnosis of pancreatic lesions. EUS and CH-EUS are also useful for staging pancreatic cancer. Moreover, EUS-guided fine-needle aspiration (EUS-FNA) is superior to other modalities in terms of cytopathological diagnosis. Although EUS-FNA has a high diagnostic ability for pancreatic cancer, the combination of EUS-FNA and CH-EUS improves the diagnostic ability by decreasing the number of false-negative cases. Thus, conventional EUS, EUS-FNA, and CH-EUS are essential in clinical practice for the diagnosis of pancreatic solid lesions.

Two-dimensional Texture Analysis Based on CT Images to Differentiate Pancreatic Lymphoma and Pancreatic Adenocarcinoma: A Preliminary Study

OBJECTIVE

To retrospectively assess the diagnostic performance of texture analysis and characteristics of CT images for the discrimination of pancreatic lymphoma (PL) from pancreatic adenocarcinoma (PA).

METHODS

Fifteen patients with pathologically proved PL were compared with 30 age-matched controls with PA in a 1:2 ratio. Patients underwent a CT scan with three phases including the precontrast phase, the arterial phase, and the portal vein phase. The regions of interest of PA and PL were drawn and analyzed to derive texture parameters with MaZda software. Texture features and CT characteristics were selected for the discrimination of PA and PL by the least absolute shrinkage and selection operator and logistic regression analysis. Receiver operating characteristic analysis was performed to assess the diagnostic performance of texture analysis and characteristics of CT images.

RESULTS

Sixty texture features were obtained by MaZda. Of these, four texture features were selected by least absolute shrinkage and selection operator. Following this, three texture features and nine CT characteristics were excluded by logistic regression analysis. Finally, "S(5, -5)SumAverg" (texture feature) and "Size" (CT characteristic) were selected for the receiver operating characteristic analysis. The AUC of "S(5, -5)SumAverg" and "Size" were to be 0.704 and 0.821, respectively, with no significance between them (p = 0.3064).

CONCLUSION

Two-dimensional texture analysis is a quantitative method for differential diagnosis of PL from PA. The diagnostic performance of both texture analysis and CT characteristics was similar.

Life-threating diarrhea and acute renal failure secondary to pancreatic VIPoma treated by surgery

Pancreatic neuroendocrine tumors represent less than 5% of all pancreatic tumors. They are a heterogeneous group of neoplasms with a diverse behavior and prognosis. Pancreatic vasoactive intestinal polypeptide tumor (VIPoma) is an exceptional tumor within this group due to its low incidence. The presence of pancreatic VIPoma should be clinically suspected in all patients with watery diarrhea, particularly when accompanied by a loss of potassium and bicarbonate and a pancreatic mass on imaging. There are other pathologies with similar symptoms; therefore, a correct differential diagnosis with an adequate treatment is essential for its management. We present the case of a 46-year-old patient who developed a prerenal kidney failure secondary to severe watery diarrhea after a diagnosis of pancreatic VIPoma. Thus, a resection was performed as the patient was rapidly deteriorating and required an intervention.

CT radiomics may predict the grade of pancreatic neuroendocrine tumors: a multicenter study

OBJECTIVE

To develop and validate a radiomics-based nomogram for preoperatively predicting grade 1 and grade 2/3 tumors in patients with pancreatic neuroendocrine tumors (PNETs).

METHODS

One hundred thirty-eight patients derived from two institutions with pathologically confirmed PNETs (104 in the training cohort and 34 in the validation cohort) were included in this retrospective study. A total of 853 radiomic features were extracted from arterial and portal venous phase CT images respectively. Minimum redundancy maximum relevance and random forest methods were adopted for the significant radiomic feature selection and radiomic signature construction. A fusion radiomic signature was generated by combining both the single-phase signatures. The nomogram based on a comprehensive model incorporating the clinical risk factors and the fusion radiomic signature was established, and decision curve analysis was applied for clinical use.

RESULTS

The fusion radiomic signature has significant association with histologic grade (p < 0.001). The nomogram integrating independent clinical risk factor tumor margin and fusion radiomic signature showed strong discrimination with an area under the curve (AUC) of 0.974 (95% CI 0.950-0.998) in the training cohort and 0.902 (95% CI 0.798-1.000) in the validation cohort with good calibration. Decision curve analysis verified the clinical usefulness of the predictive nomogram.

CONCLUSION

We proposed a comprehensive nomogram consisting of tumor margin and fusion radiomic signature as a powerful tool to predict grade 1 and grade 2/3 PNET preoperatively and assist the clinical decision-making for PNET patients.

KEY POINTS

• Radiomic signature has strong discriminatory ability for the histologic grade of PNETs. • Arterial and portal venous phase CT imaging are complementary for the prediction of PNET grading. • The comprehensive nomogram outperformed clinical factors in assisting therapy strategy in PNET patients.

MRI evaluation of pancreatic ductal adenocarcinoma: diagnosis, mimics, and staging

The radiologist's role in the evaluation of pancreatic ductal adenocarcinoma remains critical in the management of this deadly disease. Imaging plays a vital role in the diagnosis and staging of pancreatic cancer. Although CT is more commonly used for staging pancreatic cancer, MR is increasingly playing an important role in this regard. In our institution, all pancreatic malignancies undergo staging with MRI. In this pictoral essay, we illustrate the MR imaging features of pancreatic ductal adenocarcinoma and its mimics, and we also discuss pearls and pitfalls in MR staging of pancreatic carcinoma.

Periampullary Metastases from Breast Cancer: A Case Report and Literature Review

We presented a metastatic breast cancer case who was afflicted with obstructive jaundice caused by an ampullary neoplasm. Since jaundice due to periampullary metastasis from breast cancer was a rare entity, a literature review of similar cases through the PubMed database was done. A total of 23 additional cases were found. Among these 24 cases, 5 presented with periampullary metastasis synchronously with the diagnosis of breast cancer, while 19 had metachronous periampullary metastasis with an interval ranging between 1.3 and 23 years from the initial diagnosis of breast cancer to the emergence of jaundice. It is intriguing to establish a differential diagnosis for common bile tract stricture prior to tissue biopsy, even with diagnostic workups including serum tumor markers, MRI plus MRCP, ERCP with intraductal brushing, and endoscopic ultrasound, in that the clinical, radiological, and endoscopic findings of metastatic lesions overlapped extensively with those found with primary periampullary malignancies. An immunohistochemical portfolio including cytokeratin7/20 (CK7/20), homeobox protein CDX2, human epidermal growth factor receptor 2 (HER2/neu), estrogen receptor alfa (ERα), progesterone receptor (PgR), mammaglobin, gross cystic disease fluid protein-15 (GCDFP-15), and transacting T-cell-specific transcription factor (GATA-3) was helpful for differential diagnosis among cases with ambiguous microscopic features.

Pleomorphic and atypical multinucleated giant cells in solid pseudopapillary neoplasm of pancreas: A diagnostic pitfall in cytology and a review of the literature

Solid pseudopapillary neoplasm of the pancreas (SPN) is a rare low-grade malignancy typically occurring in young women. Occasionally, these neoplasms present with pleomorphic to atypical multinucleated giant tumor cells which may mimic high-grade malignancy. Our patient is a 25-year-old male who presented with one year of intermittent epigastric pain. Magnetic resonance imaging showed a 3.1 × 2.5 cm mass in the pancreas body. Endoscopic ultrasound-guided fine needle aspiration of the mass showed large pleomorphic cells and atypical multinucleated giant cells in a background of singly scattered polygonal cells. Focally, these cells surrounded delicate hyalinized to fibrovascular cores forming pseudopapillae. Immunohistochemical stains show tumor cells are positive for beta-catenin, CD10, vimentin, and CD56. Although rare surgical pathology publications have described the presence of pleomorphic to atypical multinucleated giant cells occurring in SPN, to our knowledge, this is the first case reported example focused on cytomorphologic illustration and description.

Solid Pseudo-Papillary Tumor Mimicking as Complicated Pseudocyst: Multimodality Imaging and Pathological Correlation

Pancreatic neoplasm is very rare in the pediatric population. Malignant tumors represent less than 0.2% of pediatric cancer-related mortality. Pancreas lesions can be from exocrine or endocrine origin or present themselves as cystic masses. Clinical, biological, and radiological findings usually are sufficient to establish diagnosis, but in some cases, they may be misleading. We present the case of a young patient presenting a pancreatic mass where anatomical and metabolic characteristics of the lesion were discordant to the final diagnosis.

FDG-PET CT in the evaluation of primary and secondary pancreatic malignancies

PURPOSE

Primary pancreatic carcinoma and pancreatic metastases are rare in the pediatric population. Pancreatoblastoma is the most common pancreatic malignant tumor in young children and solid-pseudopapillary tumor in teenagers. Pancreatic adenocarcinoma is extremely rare under the age of 40 and is usually associated with underlying genetic abnormalities. Secondary malignancies of the pancreas occur more frequently than primary pancreatic malignancies in children and are most commonly seen with non-Hodgkin lymphomas (NHL) and mesenchymal sarcomas. The purpose of this study was to characterize the metabolism of primary and secondary tumors of the pancreas in pediatric patients.

MATERIALS AND METHODS

A retrospective analysis of all primary and secondary pancreatic malignancies imaged with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) computed tomography (CT) was conducted.

RESULTS

Three patients with primary pancreatic cancers were identified, one each with pancreatoblastoma, solid-pseudopapillary tumor, and adenocarcinoma. Each tumor showed elevated uptake of FDG. Metastatic disease in the pancreas was identified in 12 patients-five NHL (including three Burkitt lymphomas), six sarcomas (three osteosarcomas, two rhabdomyosarcomas, and one Ewing sarcoma family tumor), and one malignant rhabdoid tumor. Elevated but variable uptake of FDG was found in each of the tumors of patients with metastatic disease within the pancreas.

CONCLUSION

Both primary malignancies and metastatic disease within the pancreas, though very rare in children, adolescents, and young adults, are metabolically active and can be functionally characterized using FDG-PET CT.

Pancreatoblastoma in a paediatric patient: anatomo-pathological aspects of a case with multiple hepatic metastases

Pancreatoblastoma is a rare paediatric malignant neoplasm. The treatment of choice is complete surgical resection. However, it is often unresectable due to its large size, local infiltration or distant metastasis. Since the condition is rare, there is currently no standard treatment regimen. We outline the case of a 4-year-old child who presented with abdominal pain and distention, together with an enlarged liver and elevated serum α-fetoprotein levels. Imaging studies showed the presence of an abnormal pancreatic tumour and multiple nodular lesions in the liver, the biopsies from which led to a diagnosis of pancreatoblastoma. In this case, the patient received cycles of neoadjuvant chemotherapy, combining cisplatin and doxorubicin. The patient subsequently underwent scheduled surgery in which the primary pancreatic lesion was resected, obtaining a circumscribed and nodular specimen measuring 7 × 6 cm and weighing 150 g. Given the extent of the metastasis, the child is currently awaiting a liver transplant.

Pancreatic Cytology

The diagnostic approach to pancreaticobiliary disease requires a multidisciplinary team in which the cytopathologist plays a crucial role. Fine-needle aspiration, obtained by endoscopic ultrasound, is the diagnostic test of choice for pancreatic lesions. Preoperative clinical management depends on many factors, many of which rely on accurate cytologic assessment. Pancreaticobiliary cytology is wrought with diagnostic pitfalls. Clinical history, imaging studies, cytology samples, and ancillary tests, including immunohistochemistry, biochemical analysis, and genetic sequencing, are integral to forming a complete diagnosis and guiding optimal patient management. This article reviews clinical aspects and the diagnostic work-up of commonly encountered diagnostic entities within the field of pancreatic cytology.

Intrapancreatic accessory spleen: Evaluation with CT and MRI

The aim of the present study was to evaluate the characteristics of computed tomography (CT) and magnetic resonance imaging (MRI), particularly diffusion-weighted imaging (DWI), in the imaging of intrapancreatic accessory spleen (IPAS). The clinical and pathological records of 9 patients, including 8 patients with IPAS and 1 patient with splenosis, were reviewed. The patients had undergone plain and triple-phase enhanced CT scanning (n=9) and MRI scanning (n=8). The lesions of the 8 IPAS patients were located in the pancreatic tail, and were round (n=3), oval (n=4) or triangular (n=1) in shape. The CT and/or MRI densities, signal intensities and dynamic enhanced patterns of the lesions were similar to those of the orthotopic spleen. In DWI images (n=5), the IPAS regions presented high signal intensity (SI), and no significant difference in the apparent diffusion coefficient determined using a b-value of 600 sec/mm² was identified between the IPAS and orthotopic spleen (P>0.05). One patient with splenosis complicated with cirrhosis had a nodule located in the pancreatic tail with an unenhanced CT value of 65 HU. In MRI examination, with the exception of the dynamic enhancement pattern, the T1-weighted, T2-weighted and DWI signals of splenosis were inconsistent with those of the normal spleen. In conclusion, in pre-contrast and post-contrast-enhanced CT and MRI images, IPAS exhibits similar characteristics to the orthotopic spleen. CT and MRI used in combination with DWI are important in the diagnosis of IPAS.

Radiological Workup of Cystic Neoplasms of the Pancreas

Pancreatic cystic lesions are being detected with increasing frequency because of increased use and improved quality of cross-sectional imaging techniques. Pancreatic cystic lesions encompass non-neoplastic lesions (such as pancreatitis-related collections) and neoplastic tumors. Common cystic pancreatic neoplasms include serous cystadenomas, mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, and solid pseudopapillary tumors. These cystic pancreatic neoplasms may have typical morphology, but at times show overlapping imaging features on cross-sectional examinations. This article reviews the classical and atypical imaging features of commonly encountered cystic pancreatic neoplasms and presents the limitations of current cross-sectional imaging techniques in accurately classifying pancreatic cystic lesions.

MR Imaging of Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) is characterized by autoimmune inflammatory destruction of the pancreatic tissue. Imaging plays an essential role in the diagnosis. AIP type 1 is the pancreatic manifestation of immunoglobulin G4 (IgG4)-related disease and is associated with IgG4-positive plasma cell infiltration and fibrosis of multiple organ systems. Type 2 is a related disease with pancreatic inflammation with or without concurrent inflammatory bowel disease. The authors demonstrate the imaging findings that are associated with the pancreatic and extra-pancreatic manifestations of AIP. They emphasize the common MR imaging and magnetic resonance cholangiopancreatography findings to help make the diagnosis of AIP.

Nonepithelial Neoplasms of the Pancreas, Part 2: Malignant Tumors and Tumors of Uncertain Malignant Potential From the Radiologic Pathology Archives

Almost all neoplasms of the pancreas are derived from pancreatic epithelial components, including the most common pancreatic mass, primary pancreatic ductal adenocarcinoma (PDAC). Nonepithelial neoplasms comprise only 1%-2% of all pancreatic neoplasms. Although some may arise directly from intrapancreatic elements, many originate from mesenchymal, hematopoietic, or neural elements in the retroperitoneal peripancreatic space and grow into the pancreas. Once these tumors reach a certain size, it can be challenging to identify their origin. Because these manifest at imaging as intrapancreatic masses, awareness of the existence and characteristic features of these nonepithelial neoplasms is crucial for the practicing radiologist in differentiating these tumors from primary epithelial pancreatic tumors, an important distinction given the vastly different management and prognosis. In part 1 of this article, the authors reviewed benign nonepithelial neoplasms of the pancreas. This article focuses on malignant nonepithelial neoplasms and those of uncertain malignant potential that can be seen in the pancreas. The most common malignant or potentially malignant nonepithelial pancreatic tumors are of mesenchymal origin and include soft-tissue sarcomas, solitary fibrous tumor, and inflammatory myofibroblastic tumor. These tumors commonly manifest as large heterogeneous masses, often containing areas of necrosis and hemorrhage. The clinical features associated with these tumors and the imaging characteristics including enhancement patterns and the presence of fat or calcification help distinguish these tumors from PDAC. Hematopoietic tumors, including lymphoma and extramedullary plasmacytoma, can manifest as isolated pancreatic involvement or secondarily involve the pancreas as widespread disease. Hyperenhancing paragangliomas or hypervascular metastatic disease can mimic primary pancreatic neuroendocrine tumors or vascular anomalies.

Multiple solid pancreatic lesions: Prevalence and features of non-malignancies on dynamic enhanced CT

OBJECTIVE

To determine the prevalence of multiple solid pancreatic lesions on dynamic enhanced CT performed for suspected pancreatic diseases, and to identify CT features of non-malignancies.

METHODS

We investigated 8096 consecutive patients who underwent dynamic enhanced CT pancreas protocol at a tertiary center over 40 months. The final clinical /pathological diagnosis served as reference standard. The diagnostic accuracy of dynamic enhanced CT for non-malignancies was calculated. A univariate and multivariate analysis was conducted to identify features that predict non-malignancies.

RESULTS

Multiple solid pancreatic lesions were identified in 121 patients. The prevalence of non-malignancies was 19.8% (24/121). The most common non-malignancy was autoimmune pancreatitis (n = 21; 17.4%). Common lesions with malignant potential included neuroendocrine neoplasia (n = 62; 51.2%), ductal adenocarcinoma (n = 15; 12.4%), metastasis (n = 9; 7.4%), and lymphoma (n = 7; 5.8%). Dynamic enhanced CT had a sensitivity of 79.2% and a specificity of 92.8% for diagnosing non-malignancies. Elevated serum IgG4 level (p < 0.001), hypo-enhancement in arterial phase (p = 0.001), hyper-enhancement in equilibrium phase (p = 0.009) and location in both proximal and distal pancreas (p = 0.036) were predictors of non-malignancies, whereas pancreatic duct morphology and vascular invasion status were not.

CONCLUSION

Multiple solid pancreatic lesions were rare, with a wide spectrum. Dynamic enhanced CT provides clues for identifying non-malignancies.

Adult pancreatoblastoma: A case report and clinicopathological review of the literature

PURPOSE

Our purpose was to report a case of adult pancreatoblastoma, and review the literature in order to assist clinicians in the management of the disease.

MATERIALS AND METHODS

The demographic, clinical, and imaging findings of 41 patients with pathologically proven pancreatoblastoma from 1986 to 2017 identified in PubMed were reviewed. The key words used for searching PubMed were: "pancreatoblastoma", "pancreatic tumor", and "adult pancreatoblastoma." We also reported the details of a case of adult pancreatoblastoma treated at our institution.

RESULTS

We identified 41 cases of adult pancreatoblastomas, and the mean age at diagnosis was 41.4 ± 17.4 years. Pancreatoblastomas occurred in the pancreatic head in 48.4% of patients, and in 39.0% of cases the tumor was >8 cm in diameter at diagnosis. Patient age and tumor size were similar between males and females (P = 0.59; P = 0.32, respectively). Metastases was present in 17 of the 41 adult patients (41.5%). No significant difference in age, sex, tumor size, and tumor location was found between patients with and without metastases (P = 0.57, 0.58, 0.64, 0.39, respectively).

CONCLUSION

Preoperative diagnosis of adult pancreatoblastoma is difficult because of the heterogeneous, variable cellular differentiation and atypical clinical and imaging features. A pancreatoblastoma should be considered when tumors in the pancreas are solid and cystic.

Surgery for pancreatic cancer: critical radiologic findings for clinical decision making

Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States, with an estimated 53,670 new cases diagnosed and an estimated 43,090 deaths in 2017. This high mortality rate is in part due to the small percentage of patients diagnosed with local disease, as well as the biologically aggressive nature of the disease. While only 10-20% of patients will present with surgically resectable disease, this is the only possible curative therapy. Five-year survival of resected pancreatic cancer ranges from 12 to 27%. The National Comprehensive Cancer Network (NCCN) guidelines recommend specific guidelines for imaging modalities used in the diagnosis and staging of pancreatic adenocarcinoma. Indeed, high-quality imaging is not only necessary to accurately stage the disease, but is critical for the determination of key clinical decision branch points such as the determination of surgical resectability. Identification of the lesion within the pancreas, the degree of extra-pancreatic extension, and potential involvement of surrounding vascular structures with the tumor are all findings necessary to classify patients as having resectable, borderline resectable, or with unresectable primary tumors. This article reviews imaging modalities used to evaluate the pancreatic cancer patient from the surgeon's perspective, with particular emphasis on determination of resectability and preoperative planning, as well as imaging in the postoperative period.

Rare pancreatic tumors

In this review, we will focus on rare pancreatic tumors. Most of these tumors do not have distinct characteristic appearances so the key to diagnosis requires a combination of imaging appearance, laboratory data, patient demographics, and associated medical syndromes in order to narrow the differential diagnosis. Nonetheless, imaging plays a vital role in narrowing the differential and guiding management. While there are many variant pathologic entities that cannot be encompassed by a single review, we aim to illustrate the imaging appearance of less common pancreatic tumors highlighting key distinctive diagnostic characteristics and discuss the implications for management. While there is overlap in the imaging appearances of many of these entities, for educational purposes, lesions will be categorized into solid (hypoenhancing and hyperenhancing), cystic lesions, mesenchymal neoplasms, and neoplasms seen in younger patients (< 40 years).

Diagnostic Challenge in Pancreatic Sarcoidosis Using Endoscopic Ultrasonography

We herein report a 55-year-old woman who presented with erythema and bilateral hilar lymphadenopathy 4 months prior to the detection of pancreatic lesions on an ultrasound. A skin biopsy showed evidence of sarcoidosis. The largest lesion in the tail of the pancreas was hypoechoic on endoscopic ultrasonography (EUS). The lesion was initially iso-enhanced on contrast enhanced-EUS (CE-EUS) but subsequently became hypoenhanced. The lesion revealed heterogeneous components of both soft and hard tissue on EUS elastography. She was ultimately diagnosed with pancreatic sarcoidosis based on the presence of noncaseating granulomas seen on pancreatic tissue retrieved through an EUS-guided fine needle aspiration biopsy.

Pancreatoblastoma With Metastatic Retroperitoneal Lymph Node and PET/CT

A previously healthy 4-year-old girl presented with petechial rash and low platelet count. There were no other symptoms. On abdominal ultrasound, a 4.7-cm heterogeneous mass was demonstrated anterior to the left kidney. An abdominal MRI subsequently performed demonstrated a heterogeneously enhancing mass at the same location extending to the pancreas and spleen. A surgical biopsy of the mass was obtained. Pathology reported a malignant epithelioid neoplasm consistent with pancreatoblastoma. The mass demonstrated intense FDG uptake on PET and an FDG avid retrocaval lymph node.

Paraduodenal pancreatitis as a mimicker of pancreatic adenocarcinoma: MRI evaluation

PURPOSE

To evaluate the MRI features of paraduodenal pancreatitis (PDP) and to define useful signs to differentiate PDP from pancreatic ductal adenocarcinoma (PDAC).

MATERIAL AND METHODS

We reviewed the MRI scans of 56 patients, 28 affected by PDP and 28 by PDAC, all pathologically proven. The following parameters were evaluated: signal intensity of the lesion on T1-, T2-WI, DWI (b800) and after contrast medium administration; presence of cysts; dilation of common hepatic duct and main pancreatic duct; focal thickening of the second portion of the duodenum; maximum diameter and volume of the lesion.

RESULTS

Both PDPs and PDACs were more frequently hypointense on T1-WI, iso-hyperintense on T2-WI, hypointense in the pancreatic phase and iso-hypointense in the venous phase (p>0.05); in the delayed phase most PDP were hyperintense (p=0.0031); on DWI 71.4% PDPs were isointense and all PDACs were hyperintense (p=0.0041). Cystic components were present in 85.7% PDPs (p=0.0011); double duct sign was present in 50% PDACs (p=0.0048); focal thickening of the duodenum was depicted in 89.3 PDPs (p=0.0012). PDPs were larger than PDACs (p=0.0003).

CONCLUSION

The most suggestive signs of PDP are: signal hyperintensity in the delayed phase, isointensity on DWI, presence of cysts, focal thickening of the duodenum and large size of the lesion.

Fluorodeoxyglucose-positron emission tomography/computed tomography performs better than contrast-enhanced computed tomography for metastasis evaluation in the initial staging of pancreatic adenocarcinoma

OBJECTIVE

To evaluate the additional role of FDG-PET/CT to the conventional multiphasic CECT in the initial staging of pancreatic adenocarcinoma.

METHODS

54 patients diagnosed with pathologically proven pancreatic malignancy underwent FDG-PET/CECT. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal and metastatic staging were calculated. The statistical difference was calculated by McNemar's test.

RESULTS

Of 54 patients, 15 had distal metastasis. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal staging were 33 vs 89%, 84 vs 100%, 67 vs 100%, 60 vs 90%, and 59 vs 95%, respectively, p < 0.001. The sensitivity, specificity, PPV, NPV, and accuracy of CECT for metastatic staging were 73, 87, 69, 89, and 83%, whereas the accuracy of PET/CT was 100%, p = 0.01. By correctly characterizing unsuspected distant lesions, PET/CT could change management in 19% of patients.

CONCLUSION

FDG-PET/CT can contribute to change in the management in almost one of every five patients of PA evaluated with the standard investigations during the initial staging.

Abdominal schwannomas: review of imaging findings and pathology

Schwannomas are typically slow growing, encapsulated benign neoplasms. Visceral schwannomas are rare, and preoperative diagnosis is challenging, as they are often confused with other neoplasms even with advanced imaging studies. Surgical excision is usually needed to establish a definitive diagnosis, as pathology is the "gold standard." We review the imaging findings of abdominal schwannomas focusing on pancreatic, gastrointestinal, and retroperitoneal/adrenal schwannomas with pathology correlation. We conclude that schwannoma should be included in the broad differential diagnosis of an abdominal mass and that when it is unnecessary radical resection can be avoided.

Dynamic nuclear polarisation: The future of imaging in oncology?

As clinical oncology evolves with new treatment options becoming available, there is an increasing demand on anatomic imaging for the assessment of patients at different stages. Imaging with hyperpolarized 13C-labelled cell substrates has the potential to become a powerful tool in many steps of clinical evaluation, offering a new metabolic metric and therefore a more personalised approach to treatment response. This articles explores the metabolic basis and potential for translation of hyperpolarised pyruvate as a dynamic nuclear polarisation probe in clinical oncology.

Imaging Patterns of Intratumoral Calcification in the Abdominopelvic Cavity

Intratumoral calcification is one of the most noticeable of radiologic findings. It facilitates detection and provides information important for correctly diagnosing tumors. In the abdominopelvic cavity, a wide variety of tumors have calcifications with various imaging features, though the majority of such calcifications are dystrophic in nature. In this article, we classify the imaging patterns of intratumoral calcification according to number, location, and morphology. Then, we describe commonly-encountered abdominopelvic tumors containing typical calcification patterns, focusing on their differentiable characteristics using the imaging patterns of intratumoral calcification.

Ectopic pancreatic tissue in the stomach: Case report

Introduction: Ectopic pancreas is a rare developmental anomaly. It is a presence of pancreatic tissue without anatomic or vascular continuity with the normally developed pancreas. The most common heterotopic site is the stomach commonly involving antrum and prepyloric region on the greater curvature or posterior wall. Ectopic pancreas is diagnosed by endoscopic ultrasound, gastroscopy and biopsy, CT scan and MRI of the abdomen, a definitive diagnosis is verified by histopathological examination. Treatment is surgical. Case report: A 56-year-old woman presented with epigastric pain, nausea and fatigue. Esophagogastroduodenoscopy showed submucosal mass in the prepyloric region, biopsy was performed. Histopathological findings described normal gastric mucosa. Endoscopic ultrasonography and CT of the abdomen showed submucosal tumor, 18 mm in diameter, located in the prepyloric region. Surgical treatment was indicated. Gastrotomy with total extraction of tumor was performed. Histopathology findings showed ectopic pancreatic tissue in the submucosal and muscular layer of the stomach. Postoperatively patient fully recovered, and in the 2 year follow-up did not develop any symptoms related to gastrointestinal tract. Conclusion: Although presentation of ectopic pancreatic tissue in stomach is a very rare condition, it should be considered during gastroitestinal diagnostic in patients with nonspecific gastrointestinal symptomatology. In most of cases, for this patients, surgery is curative and definitive solution.

Rare Case of an Epithelial Cyst in an Intrapancreatic Accessory Spleen Treated by Robot-Assisted Spleen Preserving Distal Pancreatectomy

Epithelial cyst in an intrapancreatic accessory spleen (ECIPAS) is exceedingly rare with only 57 cases reported since the first publication in 1980. Comprehensive clinical and diagnostic features remain to be clarified. We present a case of ECIPAS in a 21-year-old Philippine woman who was admitted with right upper quadrant abdominal pain. A cystic lesion in the pancreatic tail was discovered and evaluated by computed tomography and magnetic resonance images. Based on clinical and radiological features a solid pseudopapillary neoplasm was suspected. The patient underwent robot-assisted spleen preserving distal pancreatectomy. Pathological evaluation revealed a 26 mm intrapancreatic accessory spleen with a 16 mm cyst, lined by multilayered epithelium in the tail of the pancreas. The postoperative course was uneventful. Differentiating ECIPAS from (pre)malignant cystic pancreatic neoplasms based on clinical and radiological features remains difficult. When typical radiological signs can be combined with scintigraphy using Technetium-99m labelled colloid or Technetium-99m labelled erythrocytes, which can identify the solid component of the lesion as splenic tissue, it should be possible to make the right diagnosis noninvasively. When pancreatectomy is inevitable due to symptoms or patient preference, minimally invasive laparoscopic or robot-assisted spleen preserving distal pancreatectomy should be considered.

Adult pancreatoblastoma - Case report and review of literature

Most cases of pancreatoblastoma, a rare malignant epithelial tumor of the pancreas, are seen in the pediatric population. The rarity of pancreatoblastoma, the similar radiologic findings to those seen in other pancreatic lesions, and its histopathologic heterogeneity, make its preoperative diagnosis in adults a real challenge. We report ultrasound, computed tomography and magnetic resonance imaging correlative findings of a histologically proven pancreatoblastoma in a 37-year-old woman. Pancreatoblastoma should be considered in the differential diagnosis of a pancreatic mass presenting uncommon imaging features.

Left-sided pancreatic incidentalomas treated with laparoscopic approach: a report of 20 cases

BACKGROUND

The diffusion of cross-sectional imaging has recently permitted the detection of an increasing number of incidentalomas localized in the distal pancreas. Currently, there are no studies in the literature exploring the laparoscopic approach as treatment for left-sided pancreatic incidentalomas.

METHODS AND RESULTS

We report a series of 20 incidentalomas localized in the body and tail of the pancreas treated with laparoscopic surgery over the period 2010-2014. The incidental masses of our series included a great variety of histotypes and a relevant proportion of malignant lesions. In two cases, the laparoscopic procedures were converted to open surgery. No postoperative death was observed. The postoperative pancreatic fistula rate was 20 %, and the new-onset diabetes rate was 25 %.

CONCLUSIONS

Left-sided pancreatic incidentalomas in patients with minor comorbidities can be safely treated with laparoscopic approach. Only clinical trials will confirm whether laparoscopic surgery is an effective treatment for malignant lesions.

Comparison of Multidetector CT and Gadobutrol-Enhanced MR Imaging for Evaluation of Small, Solid Pancreatic Lesions

OBJECTIVE

To compare multidetector computed tomography (MDCT) and MRI for lesion conspicuity, as well as the detection and characterization of small solid pancreatic lesions (SPLs).

MATERIALS AND METHODS

193 patients with small SPLs (< 3 cm) and 52 patients with normal pancreas who underwent both multiphasic MDCT and gadobutrol-enhanced MRI were included in our study. Two radiologists blinded to the pathologic diagnoses independently reviewed those images, and determined the detection of "SPL per se" and "SPL in consideration of secondary features", the lesion conspicuity, the probability of pancreatic ductal adenocarcinoma (PDAC), and the most likely specific diagnosis.

RESULTS

The sensitivity of MRI for "detection of SPL per se" was significantly higher than that of CT in both reviewers: 92.7% (179/193) and 97.9% (189/193), respectively, for reviewer 1 (p = 0.031) and 90.7% (175/193) and 99.5% (192/193), respectively, for reviewer 2 (p < 0.001). In addition, MRI provided better lesion conspicuity than MDCT for both reviewers (p < 0.001). However, CT and MRI did not show significant difference in sensitivity for "detection of SPL in consideration of secondary features", specificity for SPL detection, and differentiation of PDAC vs. non-PDAC (p > 0.05). The accuracies of CT and MRI for making a specific diagnosis were as follows: 85.7% (210/245) vs. 86.9% (213/245), respectively, for reviewer 1 (p = 0.736), and 91.8% (225/245) vs. 93.5% (229/245), respectively, for reviewer 2 (p = 0.454).

CONCLUSION

MRI showed better lesion conspicuity than MDCT, but did not show significantly different diagnostic performance compared with MDCT for detecting and characterizing small SPLs.